1. Field of Invention
The present invention relates to a test circuit. More particularly, the present invention relates to a test circuit to test the pixel array function of a display panel.
2. Description of Related Art
Display panels are extensively used as computer monitors, televisions and as screens for mobile devices, etc. Besides the design of the pixel array and the drive circuit in the display panel, the test circuit is also an important issue in the manufacturing process of the display panel. The test circuit tests the function without affecting the normal operation of the pixel array of the display panel.
A conventional test circuit connects the test signal lines directly to the pixel array and the drive circuit. After the test process, a laser cut process is performed to cut off the test signal lines. The laser cut process raises the cost of the manufacturing process. Further, if the laser cut process doesn't completely cut off the test signal lines, the connection of the test signal lines, pixel array and the drive circuit may cause abnormal display result. Another conventional design of the test circuit is to place a transistor between the connection of the test signal circuit and the pixel array and between the connection of test signal circuit and the drive circuit. Each transistor acts as a switch to turn off during the normal operation of the pixel array and the drive circuit. However, the transistor may suffer from static electricity and further cause damage to the pixel array and the drive circuit. Also, the difference of the manufacturing process among the transistors is easy to make a mura situation on the display panel when the test signals are fed.
Accordingly, what is needed is a test circuit to prevent the static electricity and lower the effect of the difference between the transistors to overcome the above issues. The present invention addresses such a need.